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CHEMISTRY 1201, Lecture section 02 and 03
SAMPLE EXAM 2 - SPRING 2002 - SOLUTIONS

PART 1 - Multiple Choice

1. The wavelength of radiation from a cellular telephone, which emits at a frequency of 879 MHz is?

a) 2.93 m
b) 2.93 x 10^-8 m
c) 34.1 m
d) 341 m
e) 3.4 x 10^-1 m

2. The energy of a photon with a wavelength of 400 nm is?

a) 4.97 x 10^-28J
b) 4.97 x 10^-19J
c) 1.33 x 10^-15J
d) 7.5 x 10⁵J
e) 7.5 x 10¹⁴J

3. The sole electron in an H atom undergoes a transition from n = 3 to n = 1. Which TWO statements are true?

a) energy is lost by the atom
b) energy is gained by the atom
c) a photon of radiant energy is absorbed
d) a photon of radiant energy is emitted
e) none of the above

4. Which of the statements concerning the quantum mechanical description is FALSE?

a) Orbitals have no physical meaning with respect to the atom, they are merely mathematical entities.
b) Electrons exhibit both wave and particle properties.
c) The square of the wavefunction allows one to define the electron probability distribution within an atom.
d) Electrons inhabit circular orbits.
e) Electromagnetic radiation exhibits both wave and particle properties.

5. Which of the following sets of quantum numbers ARE ALLOWED?

a) n = 0, l = 0, m_l = 0
b) n = 1, l = 0, m_l = 0
c) n = 2, l = 1, m_l = -2
d) n = 6, l = 5, m_l = -5
e) n = 6, l = -4, m_l = 5

6. Consider a balloon picture for a 2p_z (Fig. 6.22b left). Identify which of the following statements is FALSE.

a) There is a zero probability of finding an electron on the nucleus.
b) There is a 90% probability of the electrons in this orbital being located within the balloon.
c) Electrons in this orbital are always located somewhere on the surface of the balloon.
d) The largest probability of finding an electron in this orbital is along the z axis.
e) Only two electron may inhabit the 2p_z orbital.

Answer the next four questions using the information given below:

7. Identify the electron configuration that violates Hund's rule: b

8. Identify the electron configuration that violates Pauli's Exclusion Principle: e

9. Identify the valence electron configuration for Se^2-: d

10. Which of the electron configurations is completely ridiculous?: a (because you cannot have 2s and 2p subshells AFTER [Ar]!)

11. Identify which of the following statements concerning ionization energy (I) is FALSE.

a) Ionization energy increases in the order I₁ < I₂ < I₃.
b) Ionization energy is the energy required to remove an electron from a solid atom or ion.
c) Some of the largest differences in ionization energies occur when going from removing valence electrons to removing core electrons.
d) First ionization energy decreases going down a group.
e) none of the above.

12. Identify which of the following statements concerning atomic radii is FALSE.

a) Atomic radii increase going down a group because of the increase in orbital sizes and a successive increase in the outermost principle quantum level.
b) The atomic radius is only an estimation of the actual size of an atom.
c) Atomic radii are often called bonding radii as they are determined from the distances between atoms that are covalently bonded to one another.
d) Atomic radii decrease going right to left in the periodic table because of an increase in Z_eff.
e) none of the above.

13. The polarity of a covalent bond can be estimated using the electronegativity differences between the atoms involved in that bond.

a) true
b) false

14. Place the bonds, C-H, O-H and H-H in order of decreasing bond polarity.

a) H-H > C-H > O-H
b) O-H > H-H > C-H
c) O-H > C-H > H-H
d) C-H > O-H > H-H
e) H-H > O-H > C-H

15. Identify a set of isoelectronic atoms/ions.

a) Na⁺, Mg ²⁺, S ^2-, Cl ^-, Ar
b) F ^-, Cl ^-, Br ^-, I ^-, At ^-
c) Ca ²⁺, K ⁺, Ar, Cl ^-, S ^2-
d) Fe ²⁺, Co ²⁺, Ni ²⁺, Cu ²⁺, Zn ²⁺
e) none of the above

16. Electronegativity differences can be tentatively used to predict whether an ionic or a covalent bonding will occur between atoms.